<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="#">
    <style>
    p{
        height: 100px;            
        background-color: blueviolet;
        line-height: 100px;
        font-family: sans-serif;
    }
    .father{
        background-color: yellow;
        height: 50px;
    }
    .son {
        height: 20px;
        
    }
    div {
        background-color: #fff;
        width: 500px;
        width: 500px;
        height: 200px;
        background-color: #fff;
    }
      </style>
</head>
<body>
    <a href="#" target="_blank"></a>
    <a>This is the first line of a paragraph. This is the second line of a paragraph.</p>
    <P> A <br> B</P>
    <div class="father">
        <div class="son"></div>
    </div>
    <div class="class"></div>
    <div></div>
    <a href=""></a>
    <div>
        <p></p>
    </div>
    <span></span><span></span><span></span>
    <div>111</div>
    <ul>
        <li class="test3"></li>
        <li class="test4"></li>
        <li class="test5"></li>
        <li class="test6"></li>
        <li class="test7"></li>
    </ul>
    <ul>
        <li class="index1"></li>
        <li class="index2"></li>
        <li class="index3"></li>
        <li class="index4"></li>
        <li class="index5"></li>
    </ul>
</body>
</html>